Madabhushi Anant, Udupa Jayaram K
Department of Biomedical Engineering, Rutgers The State University of New Jersey, 617 Bowser Road, Room 101, Piscataway, New Jersey 08854, USA.
Med Phys. 2006 Sep;33(9):3426-34. doi: 10.1118/1.2335487.
Image intensity standardization is a post-acquisition processing operation designed for correcting acquisition-to-acquisition signal intensity variations (non-standardness) inherent in Magnetic Resonance (MR) images. While existing standardization methods based on histogram landmarks have been shown to produce a significant gain in the similarity of resulting image intensities, their weakness is that in some instances the same histogram-based landmark may represent one tissue, while in other cases it may represent different tissues. This is often true for diseased or abnormal patient studies in which significant changes in image intensity characteristics may occur. In an attempt to overcome this problem, in this paper, we present two new intensity standardization methods based on two scale concepts developed in Madabhushi et al. [Computer Vision Image Understanding 101, 100-121 (2006)] for image processing applications. These scale concepts are utilized in this paper to accurately determine principal tissue regions within MR images. Landmarks derived from these regions are used to perform intensity standardization. The new methods were qualitatively and quantitatively evaluated on a total of 67 clinical three dimensional (3D) MR images corresponding to four different protocols and to normal, Multiple Sclerosis (MS), and brain tumor patient studies. The new scale-based methods were found to be better than the existing methods, with a significant improvement observed for severely diseased and abnormal patient studies.
图像强度标准化是一种采集后处理操作，旨在校正磁共振（MR）图像中固有的采集间信号强度变化（非标准化）。虽然基于直方图标志点的现有标准化方法已被证明能在所得图像强度的相似性方面带来显著提升，但其缺点在于，在某些情况下，相同的基于直方图的标志点可能代表一种组织，而在其他情况下可能代表不同的组织。对于患病或异常患者的研究而言，情况往往如此，因为图像强度特征可能会发生显著变化。为了克服这一问题，在本文中，我们基于Madabhushi等人[《计算机视觉与图像理解》101, 100 - 121 (2006)]中为图像处理应用所开发的两个尺度概念，提出了两种新的强度标准化方法。本文利用这些尺度概念来准确确定MR图像中的主要组织区域。从这些区域得出的标志点用于执行强度标准化。我们对总共67幅临床三维（3D）MR图像进行了定性和定量评估，这些图像对应四种不同的协议以及正常、多发性硬化（MS）和脑肿瘤患者的研究。结果发现，基于新尺度的方法优于现有方法，对于病情严重和异常的患者研究有显著改善。
